I guess this could be an easy addition and would make the Qu even more flexible.
Sending FX mix to the stage adds another (dry, no EQ, no Delay etc.) monitor mix.
Sending ST/CH (instead of LR) would allow to easily add some external analog mastering device.
This is basically the same as I suggested: https://community.allen-heath.com/forums/topic/patchable-input-with-ab168
yep, somehow missed that…